#include "cache.h"
#include "commit.h"
#include "sequencer.h"
#include "rebase-interactive.h"
#include "strbuf.h"
#include "commit-slab.h"
#include "config.h"

enum missing_commit_check_level {
        MISSING_COMMIT_CHECK_IGNORE = 0,
        MISSING_COMMIT_CHECK_WARN,
        MISSING_COMMIT_CHECK_ERROR
};

static enum missing_commit_check_level get_missing_commit_check_level(void)
{
        const char *value;

        if (git_config_get_value("rebase.missingcommitscheck", &value) ||
                        !strcasecmp("ignore", value))
                return MISSING_COMMIT_CHECK_IGNORE;
        if (!strcasecmp("warn", value))
                return MISSING_COMMIT_CHECK_WARN;
        if (!strcasecmp("error", value))
                return MISSING_COMMIT_CHECK_ERROR;
        warning(_("unrecognized setting %s for option "
                  "rebase.missingCommitsCheck. Ignoring."), value);
        return MISSING_COMMIT_CHECK_IGNORE;
}

void append_todo_help(unsigned edit_todo, unsigned keep_empty,
                      struct strbuf *buf)
{
        const char *msg = _("\nCommands:\n"
"p, pick <commit> = use commit\n"
"r, reword <commit> = use commit, but edit the commit message\n"
"e, edit <commit> = use commit, but stop for amending\n"
"s, squash <commit> = use commit, but meld into previous commit\n"
"f, fixup <commit> = like \"squash\", but discard this commit's log message\n"
"x, exec <command> = run command (the rest of the line) using shell\n"
"b, break = stop here (continue rebase later with 'git rebase --continue')\n"
"d, drop <commit> = remove commit\n"
"l, label <label> = label current HEAD with a name\n"
"t, reset <label> = reset HEAD to a label\n"
"m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]\n"
".       create a merge commit using the original merge commit's\n"
".       message (or the oneline, if no original merge commit was\n"
".       specified). Use -c <commit> to reword the commit message.\n"
"\n"
"These lines can be re-ordered; they are executed from top to bottom.\n");

        strbuf_add_commented_lines(buf, msg, strlen(msg));

        if (get_missing_commit_check_level() == MISSING_COMMIT_CHECK_ERROR)
                msg = _("\nDo not remove any line. Use 'drop' "
                         "explicitly to remove a commit.\n");
        else
                msg = _("\nIf you remove a line here "
                         "THAT COMMIT WILL BE LOST.\n");

        strbuf_add_commented_lines(buf, msg, strlen(msg));

        if (edit_todo)
                msg = _("\nYou are editing the todo file "
                        "of an ongoing interactive rebase.\n"
                        "To continue rebase after editing, run:\n"
                        "    git rebase --continue\n\n");
        else
                msg = _("\nHowever, if you remove everything, "
                        "the rebase will be aborted.\n\n");

        strbuf_add_commented_lines(buf, msg, strlen(msg));

        if (!keep_empty) {
                msg = _("Note that empty commits are commented out");
                strbuf_add_commented_lines(buf, msg, strlen(msg));
        }
}

int edit_todo_list(struct repository *r, unsigned flags)
{
        struct strbuf buf = STRBUF_INIT;
        const char *todo_file = rebase_path_todo();

        if (strbuf_read_file(&buf, todo_file, 0) < 0)
                return error_errno(_("could not read '%s'."), todo_file);

        strbuf_stripspace(&buf, 1);
        if (write_message(buf.buf, buf.len, todo_file, 0)) {
                strbuf_release(&buf);
                return -1;
        }

        strbuf_release(&buf);

        transform_todo_file(r, flags | TODO_LIST_SHORTEN_IDS);

        if (strbuf_read_file(&buf, todo_file, 0) < 0)
                return error_errno(_("could not read '%s'."), todo_file);

        append_todo_help(1, 0, &buf);
        if (write_message(buf.buf, buf.len, todo_file, 0)) {
                strbuf_release(&buf);
                return -1;
        }

        strbuf_release(&buf);

        if (launch_sequence_editor(todo_file, NULL, NULL))
                return -1;

        transform_todo_file(r, flags & ~(TODO_LIST_SHORTEN_IDS));

        return 0;
}

define_commit_slab(commit_seen, unsigned char);
/*
 * Check if the user dropped some commits by mistake
 * Behaviour determined by rebase.missingCommitsCheck.
 * Check if there is an unrecognized command or a
 * bad SHA-1 in a command.
 */
int todo_list_check(struct todo_list *old_todo, struct todo_list *new_todo)
{
        enum missing_commit_check_level check_level = get_missing_commit_check_level();
        struct strbuf missing = STRBUF_INIT;
        int res = 0, i;
        struct commit_seen commit_seen;

        init_commit_seen(&commit_seen);

        if (check_level == MISSING_COMMIT_CHECK_IGNORE)
                goto leave_check;

        /* Mark the commits in git-rebase-todo as seen */
        for (i = 0; i < new_todo->nr; i++) {
                struct commit *commit = new_todo->items[i].commit;
                if (commit)
                        *commit_seen_at(&commit_seen, commit) = 1;
        }

        /* Find commits in git-rebase-todo.backup yet unseen */
        for (i = old_todo->nr - 1; i >= 0; i--) {
                struct todo_item *item = old_todo->items + i;
                struct commit *commit = item->commit;
                if (commit && !*commit_seen_at(&commit_seen, commit)) {
                        strbuf_addf(&missing, " - %s %.*s\n",
                                    find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV),
                                    item->arg_len,
                                    todo_item_get_arg(old_todo, item));
                        *commit_seen_at(&commit_seen, commit) = 1;
                }
        }

        /* Warn about missing commits */
        if (!missing.len)
                goto leave_check;

        if (check_level == MISSING_COMMIT_CHECK_ERROR)
                res = 1;

        fprintf(stderr,
                _("Warning: some commits may have been dropped accidentally.\n"
                "Dropped commits (newer to older):\n"));

        /* Make the list user-friendly and display */
        fputs(missing.buf, stderr);
        strbuf_release(&missing);

        fprintf(stderr, _("To avoid this message, use \"drop\" to "
                "explicitly remove a commit.\n\n"
                "Use 'git config rebase.missingCommitsCheck' to change "
                "the level of warnings.\n"
                "The possible behaviours are: ignore, warn, error.\n\n"));

leave_check:
        clear_commit_seen(&commit_seen);
        return res;
}